Although the cardiovascular consequences of clinical or "overt" dysthyroidism are well known and treatment relatively well established, subclinical dysthyroidism remains a controversial topic, both regarding its cardiovascular effects and the best methods for its management. Subclinical hyperthyroidism is frequent among the elderly, usually associated with multinodular goiter. Although several epidemiologic studies have demonstrated that subclinical hyperthyroidism is associated with an increased risk of atrial fibrillation and high cardiovascular mortality, solid practical data on which management can be based are not currently available. The risks related to subclinical hypothyroidism appear essentially vascular but a conclusive assessment must await further epidemiologic surveys.